A New Corydoras from Floodplain Swamps of the São Francisco River

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Digitale Literatur/Digital Literature

Zeitschrift/Journal: Spixiana, Zeitschrift für Zoologie

Jahr/Year: 2016

Band/Volume: 039

Autor(en)/Author(s): Ottoni Felipe Polivanov, Barbosa Maria A., Katz Axel M.

Artikel/Article: A new Corydoras from floodplain swamps of the São Francisco river basin, northeastern Brazil (Teleostei, Siluriformes, Callichthyidae) 131-140 ©Zoologische Staatssammlung München/Verlag Friedrich Pfeil; download www.pfeil-verlag.de

SPIXIANA 39 1 131-140 München, September 2016 ISSN 0341-8391

A new Corydoras from floodplain swamps of the São Francisco river basin, northeastern Brazil

(Teleostei, Siluriformes, Callichthyidae)

Felipe P. Ottoni, Maria A. Barbosa & Axel M. Katz

Ottoni, F. P., Barbosa, M. A. & Katz, A. M. 2016. A new Corydoras from floodplain swamps of the São Francisco river basin, northeastern Brazil (Siluriformes, Call ichthyidae). Spixiana 39 (1): 131-140. Corydoras costai is a new species described from seasonal swamps adjacent to the upper Rãs river of the Caatinga, tributary of the São Francisco river basin, north eastern Brazil. The new species, as well as C. difluviatilis, differ from all other Corydoradinae by having parapophyses of fourth free vertebra reduced and sepa rated from each other, not fused into a haemal arch. Corydoras costai shares a unique colour pattern with C. garbei and C. difluviatilis, differing from both C. garbei and C. difluviatilis by having fewer rib pairs; from. C. garbei by having odontodes pre sent on infraorbitals and opercle, and nuchal plate not in contact with supraoc cipital plate; and differing from C. difluviatilis by having five well delimited large dark brown blotches from the caudal fin base to the posterior margin of opercle, along the junction of dorsal and ventral plates on the midline of body, lower region of cleithrum dark brown, first haemal arch present on sixth free vertebra, fewer precaudal vertebra, fewer not segmented rays on anal fin, a shorter head and a deeper head. The new species shares with Corydoras difluviatilis the lack of contact between the supraoccipital and nuchal plate, small degree of ossification of the second hypobranchial and large mesial expansions on the first and second infraor bitals; which suggest a basal position within the Corydoradinae. The serrations on posterior margin of pectoral-fin spine revealed to be a polymorphic character in C. costai. Felipe P. Ottoni, Maria A. Barbosa & Axel M. Katz, Laboratório de Sistemática e Evolução de Peixes Teleósteos, Departamento de Zoologia, Universidade Federal do Rio de Janeiro, Cidade Universitária, Caixa Postal 68049, CEP 21994-970, Rio de Janeiro, RJ, Brazil; e-mail: [email protected], [email protected], [email protected] Felipe P. Ottoni, Laboratório de Sistemática e Ecologia de Organismos Aquáticos, Centro de Ciências Agrárias e Ambientais, Universidade Federal do Maranhão, Caixa Postal 70, CEP 65500-000, Chapadinha, MA, Brazil

Introduction 170 (Reis 2003, Ferraris 2007, Fuller & Evers 2005, Eschmeyer 2014), being the most speciose catfish Corydoras Lacépède, 1803 is an armored corydora genus. It is distributed along the Cis-Andean river dine catfish genus characterized by two longitudinal basins of South America, occurring in a variety of series of dermal plates and small size (25-120 mm habitats, such as shallow ponds, marshes, rivers, SL) (Reis 2003, Axenrot & Kullander 2003). Among streams and associated flooded areas (Axenrot & the more than 200 valid species of the Callichthyidae Kullander 2003, Britto & Lima 2003, Britto et al. 2007). (Eschmeyer, 2014), Corydoras currently includes over Despite the great number of species described

131 ©Zoologische Staatssammlung München/Verlag Friedrich Pfeil; download www.pfeil-verlag.de in recent years, few taxonomic revisions were per Corydoras acutus Cope, 1872: UFRJ 4645, 2 c&s, formed (Nijssen 1970, Nijssen & Isbrücker 1976) es 29.9-33.3 mm SL; rio Curibara, Ballivia province, Beni, tablishing species groups in Corydoras. Consequently, Bolivia; C. Starnes et al., 31 Aug. 1987. the phylogenetic relationships of its congeners are Corydoras aeneus (Gill, 1858): UFRJ 4546, 1 c&s; still not fully understood, as well as the monophyly aquarium material. UFRJ 3847, 15, 28.2-57.4 mm SL; Plaisance village, Gunupia, Trinidad, South America; no of the genus and some species groups (Britto & data about collector, 03 Dec. 1952. UFRJ 3017, 5, 34.9- Castro 2002, Britto 2003, Britto & Lima 2003, Britto 36.8 mm SL, Buriti palms 15 km from Aparecida do et al. 2007). Taboado, Mato Grosso do Sul state; W. Costa et al., 18 The new species herein described was collected Sept. 1994. in seasonal swamps adjacent to the upper Rãs river Corydoras arcuatus Elwin, 1938: UFRJ 4644, 2 c&s, of the Caatinga, tributary of the São Francisco river 34.3-38.5 mm SL; rio Negro, Peru; no data about collec basin, northeastern Brazil. tor, Mar. 1963. Corydoras baderi Geisler, 1969: UFRJ 4640, 2 c&s, 23.8-26.4 mm SL; tributary of the stream Palbara, Nick Materials and methods erie, Surinme; Vari et al., 16 Sep. 1980. UFRJ 4620, 2, 25.2-25.5 mm SL; tributary of the stream Palbara, Nick Material is deposited in the following institutions: MCP, erie, Surinme; Vari et al., 16 Sep. 1980. Museu de Ciências e Tecnologia da Pontifícia Universi Corydoras blochi Nijssen, 1971: UFRJ 3781, 6, 28.1- dade Católica do Rio Grande do Sul, Pontifícia Univer 35.4 mm SL; Igarapé Puraquequara, Ourém, Belém sidade Católica do Rio Grande do Sul, Brazil; and UFRJ, municipality, Pará state; A. Sarraf et al., 07-08 Aug. Instituto de Biologia, Universidade Federal do Rio de 1996. UFRJ 4527, 2 c&s, 29.3-37.4 mm SL; Igarapé Pura Janeiro, Rio de Janeiro, Brazil. Morphometric and meri quequara, Pará state, A. Sarraf et al., 08 Aug. 1996. stic data were taken according to Reis (1997) and Britto Corydoras difluviatilis Britto & Castro, 2002: MNRJ & Castro (2002) for anal fin spine length and vertebral 19739, 1 (Paratype), 41.8 mm SL; Rio Paranaíba basin, counts. SL means standard length and HL head length. Catalão municipality, Minas Gerais state, F. Bockmann Measurements were taken on the left side of each et al., 17 Sept. 1999; MNRJ 19910, 13 (Paratypes), 3 c&s, specimen with digital calipers under a stereomicro 29.0-38.9 mm SL; Catalão municipality, Minas Gerais scope. Nomenclature for latero-sensory canals follows state, F. Bockmann et al., 20 Nov. 1999. MNRJ 19913, 1 Schaefer & Aquino (2000). Osteological studies were (Paratype), 36.9 mm SL, Catalão municipality, Minas made on cleared and counterstained (c&s) specimens Gerais state, F. Bockmann et al., 21 Nov. 1999. MNRJ prepared according to Taylor & Van Dyke (1985); os 19912, 2 (Paratypes), 23.3-28.9 mm SL, Catalão munici teological terminology follows Reis (1998). Tooth and pality, Minas Gerais state, F. Bockmann et al., 21 Nov. vertebra counts were only based on cleared and coun 1999. MNRJ 19737, 12 (Paratypes), 3 c&s, 30.1-38.8 mm terstained specimens. SL; Campo Alegre de Goiás, rio Paranaíba basin Catalão The species concept herein adopted follow De municipality, Minas Gerais state, C. Figueiredo et al., 26 Queiroz (2007), and for the species delimitation we use Sept. 1999. MNRJ 19735, 1 (Paratype), 37.7 mm SL, rio the Population Aggregation Analysis method (PAA) Paranaíba basin, Catalão municipality, Minas Gerais proposed by Davis & Nixon (1992). State, C. Figueiredo & F. Bockmann, 24 September 1999. MNRJ 19736, 2 (Partypes), 13.2-19.3 mm SL, rio Parana Comparative material íba basin, Catalão municipality, Minas Gerais State, C. Figueiredo & F. Bockmann, 24 September 1999. MNRJ Aspidoras belenos Britto, 1998: UFRJ 1206, 2 (paratypes), 19909, 6 (Paratypes), 18.4-39.9 mm SL, rio Paranaíba 23.2-25.5 mm SL; rio Suspiro, tributary from the rio das basin, Catalão municipality, Minas Gerais State, F. Bo Mortes, 57 km south from Paranatinga, Mato Grosso ckmann et al., 20 Nov. 1999. MNRJ 19911, 1 (Paratype), state; W. Costa et al.; 09 Feb. 1993. UFRJ 4419, 2 c&s 35.5 mm SL, rio Paranaíba basin, Catalão municipality, (paratypes); stream on the road Primavera do Leste-Pa Minas Gerais State, F. Bockmann et al., 21 Nov. 1999. ranatinga, 82 km north from Primavera do Leste, rio das Corydoras ehrhardti Steindachner, 1910: UFRJ 2251, Mortes basin, Mato Grosso do Sul state; W. Costa et al., 3, 38.4-42.8 mm SL; dam of Vassouras, Curitiba muni 1996. cipality, Paraná state; R. Castro, 12 Feb. 1977. UFRJ 4423, Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976: 1 c&s; Campo Alegre, Santa Catarina state; S. Potch et UFRJ 4544, 1 c&s; aquarium material. al., 1996. Aspidoras microgalaeus Britto, 1998: UFRJ 1247, 1 Corydoras elegans Steindachner, 1876: UFRJ 3782, 1, (paratype), 24.3 mm SL; tributary from the rio Culuene, 36.5 mm SL; Igarapé Puraquequara, Ourém, Belém km 86 from the road Paranatinga-Canarana, Mato Gros municipality, Pará state; A. Sarraf et al., 07-08 Aug. so state; W. Costa et al., 12 Feb. 1993. UFRJ 1385, 2 1996. UFRJ 4425, 2 c&s; Igarapé Puraquequara, Ourém, (paratypes), 26.6-34.7 mm SL; stream 67 km north from Belém municipality, Pará state; A. Sarraf et al., 07-08 Paranatinga, rio Xingú basin; W. Costa et al., 10 Feb. Aug. 1996. 1993. UFRJ 4539, 2 c&s (paratypes); tributary from the Corydoras garbei Ihering, 1911: MNRJ 15778, 6, 22.9- rio Culuene, km 86 from the road Paranatinga-Canara 36.9 mm SL, rio Verde Grande, Janauba municipality, na, Mato Grosso state; W. Costa et al., 12 Feb. 1993. Minas Gerais state, D. Moraes et al., 24-30 Sept. 1990.

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MNRJ 15823, 8, 25.3-43.0 mm SL, rio Peruaçu, Itacaram 6, 31.2-58.4 mm SL, stream 28 km north of BR-101, bi municipality, Minas Gerais state, D. Moraes et al., Itanhaém municipality, São Paulo state; W. Costa et al., 24-30 Sept. 1990. 14 Oct. 2005. Corydoras hastatus Eigenmann & Eigenmann, 1888: UFRJ 3654, 5, 16.3-22.0 mm SL; rio Miranda, road be tween Miranda and Bodoquena, Mato Grosso do Sul Results state; W. Costa et al., 21 Apr. 1996. UFRJ 3659, 3, 11.3- 17.0 mm SL; pool between km 23 and 29 of the road Corydoras costai spec. nov. between Casal Vasco and Vila Bela, Mato Grosso state; Figs 1A-C and 2A-D W. Costa et al., 29 Apr. 1996. UFRJ 4529, 1 c&s, 14.7 mm SL; rio Miranda, road between Miranda and Bodoquena, Holotype. UFRJ 7790, 44.7 mm SL; Brazil, Estado da Mato Grosso do Sul state; W. Costa et al., 21 Apr. 1996. Bahia. Município de Guanambi, swamp on BR-030, 3 km Corydoras julii Steindachner, 1906: UFRJ 3779, 59, east from Guanambi (14°11'08" S 42°44'20" W / altitude 20.4-38.0 mm SL; Iguarapé Puraquequara, Ourém, Be 522 m); W. Costa, M. A. Barbosa, B. Costa, C. P. Bove, lém municipality, Pará state; A. Sarraf et al., 07-08 Aug. J. Ferreira & A. M. Katz, 7 Feb. 2010. 1996. UFRJ 4433, 2 c&s, 24.1-27.6 mm SL; Iguarapé Pu raquequara, Ourém, Belém municipality, Pará state; A. Paratypes. UFRJ 7789, 10, 21.8-37.3 mm SL; collected Sarraf et al., 1996. with holotype. UFRJ 7791, 6 (c&s), 21.8-37.3 mm SL; Corydoras melanistius Regan, 1912: UFRJ 4434, 1 c&s; collected with holotype. MCP 48169, 2, 24.3-24.4 mm upper rio Jatapú, São João da Baliza, Roraima state; SL; collected with holotype. Pinishi, 1994. Corydoras nanus Nijssen & Isbrücker, 1967: UFRJ Diagnosis. Corydoras costai is distinguished from all 4641, 2 c&s, 5 miles west from Telefe, Capavara vilage, its congeners, except to C. garbei Ihering, 1911 and Amazonas state; H. Axelrod, Mar. 1974. C. difluviatilis Britto & Castro, 2002, by having an Corydoras napoensis Nijssen & Isbrücker, 1986: UFRJ unique colour pattern characterized by the presence 4622, 2, 34.3-35.7 mm SL; Camp. Trapiche La Pescana, of series of large irregular dark brown blotches on Beni, Bolívia; H. Ortega et al., 30 Jul. 1988. dorsal and lateral surfaces of body from anterior Corydoras nattereri Steindachner, 1876: UFRJ 0025, most lateral plates to caudal peduncle (Figs 1, 2, 3 8, 27.3-34.0 mm SL; rio Regamé, Araruama municipali and 4) (vs. absence of blotches or presence of small ty, Rio de Janeiro state; W. Costa, 12 Oct. 1984. UFRJ blotches or dots). The new species is distinguished 0031, 8, 31.7-45.1 mm SL; tributary of rio Piloto (UFRRJ), Itaguaí municipality, Rio de Janeiro state; W. Costa, 06 from all its congeners, except to C. difluviatilis, Aug. 1981. UFRJ 0928, 2, 35.0-37.7 mm SL; Tupinambás by having parapophyses of fourth free vertebra farm, Itaguaí municipality, Rio de Janeiro state; M. reduced (Fig. 5) (vs. well developed in other spe Melgaço & E. Vicente, 08 Apr. 1992. cies of Corydoras) and separated from each other, Corydoras paleatus (Jenyns, 1842): UFRJ 4213, 9, not fused into a haemal arch (vs. contacting each 16.4-26.6 mm SL; temporary lagoon on the road to lagoa other and fused into a haemal arch in all the other Mirim, near arroio Grande, 10 km east from BR-114; W. species of Corydoras). Corydoras costai differs from Costa et al., 19 Jul. 1997. C. garbei and C. difluviatilis by having fewer pairs of Corydoras polystictus Regan, 1912: UFRJ 3849, 20, ribs (5 in C. costai vs. 6-7 in C. difluviatilis and 8 in 25.0-26.9 mm SL; rio Itenez, 10 km of Costa Marques, C. garbei); and from C. garbei by having odontodes Mamoré, Beni, Bolívia; R. Bailey & R. Ramos, 10 Sep. present on infraorbitals and opercle (vs. absent) and 1964. UFRJ 0440, 14, 24.0-32.5 mm SL; tributary of the rio Aripuanã (BR-174), Mato Grosso state; S. Kullander nuchal plate not in contact with supraoccipital plate & K. Tànizaki, 15 Oct. 1989. (Fig. 6) (vs. plates in contact). The new species differs Corydoras schwartzi Rössel, 1963: UFRJ 4542, 1 c&s, from C. difluviatilis having five well delimited large aquarium material. Corydoras sterbai Knaack, 1962: UFRJ dark brown blotches from the caudal fin base to the 4424, 1, 42.8 mm SL; tributary of the rio Aripuanã, posterior margin of opercle, along the junction of Suina municipality, Mato Grosso state; K. Tanizaki et dorsal and ventral plates on the midline of body (vs. al., 15 Oct. 1989. large spots of flank diffused, randomly distributed), Corydoras zigatus Eigenmann & Allen, 1942: UFRJ lower region of cleithrum dark brown (vs. with a 4643, 2 c&s, 33.1-37.2 mm SL; rio Negro, Peru; N. Chi large round patch of orange pigmentation), first richigno, Mar. 1963. haemal arch present on sixth free vertebra (vs. first Scleromystax barbatus (Quoy & Gaimard, 1824): UFRJ haemal arch present on fifth free vertebra), fewer 3204, 2, 44.6-50.6 mm SL; Cachoeiras de Macacu muni cipality, Rio de Janeiro state; no data about collector, 7 precaudal vertebra (7-9 vs. 10), fewer not segmented Dec. 1976. UFRJ 2268, 2, 55.0-55.3 mm SL; rio Guapiaçu, rays on anal fin (i vs. ii), a shorter head (head length Cachoeiras de Macacu municipality, Rio de Janeiro 32.0-35.8 % mm SL vs. 38.2-46.0 % mm SL) and a state; M. Pompeu, 7 Dec. 1976. deeper head (head depth 90.7-96.6 % mm HL vs. Scleromystax macropterus (Regan, 1913): UFRJ 7228, 77.4-88.8 % mm HL).

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Fig. 1. Corydoras costai spec. nov.: UFRJ 7790, 44.7 mm SL (holotype), Brazil, Bahia state, Guanambi municipality, 14°11'8.8" S 42°44'20.4" W/altitude 522 m. A. Lateral view; B. dorsal view; C. ventral view.

Description (Fig. 1A); roughly triangular in dorsal view (Fig. 1B). Dorsal profile of body convex from tip of supraoc Morphometric data are presented in Table 1. Head cipital process to origin of dorsal fin; slightly straight compressed with slightly convex dorsal profile from this point to posterior-most dorsal fin ray.

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A A

B B

C C

D D

Fig. 2. Lateral view of Corydoras costai spec. nov., UFRJ Fig. 3. Lateral view of Corydoras difluviatilis. A. MNRJ 7789. A. 32.7 mm SL; B. 25.2 mm SL; C. 25.0 mm SL; 19913, 36.9 mm SL; B. MNRJ 19739, 41.8 mm SL; C. MNRJ D. 24.2 mm SL. 19910, 39.3 mm SL; D. MNRJ 15823, 36.2 mm SL.

Post-dorsal fin body profile slightly concave. Ventral in cross section at pectoral fin, gradually becoming profile of body nearly straight from isthmus to anal compressed toward caudal fin. Snout rounded or fin origin, slightly convex along region of pectoral slightly pointed (Figs 1 and 2). and pelvic fin bases. Profile from anal fin origin to Eye round, located laterally on head; orbit delim caudal fin base markedly concave. Body cylindrical ited dorsally by frontal and sphenotic, ventrally by

A B

Fig. 4. Lateral view of Corydoras garbei. A. MNRJ 15823, 41.3 mm SL; B. MNRJ 15778, 36.9 mm SL.

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First haemal arch Fig. 5. Lateral view of the first precaudal vertebrae of Corydoras costai spec. nov., UFRJ 7791. Scale bar = 1 mm. infraorbitals. Anterior and posterior nares proximal, equal to orbit diameter. Maxillary barbel, usually only separated by ﬂap of skin. Anterior nares tubu reaching anteroventral limit of gill opening. Outer lar. Posterior nares close to anterodorsal margin of mental barbel slightly longer than maxillary barbel. orbit, separated from it by distance equal than nares Inner mental barbel fleshy. Small rounded papillae diameter. Mouth small, sub-terminal, width nearly covering entire surface of all barbels, upper and

Table 1. Morphometric data of Corydoras costai spec. nov. Abbreviations: H, holotype; R, range; M, mean; SD, stan dard deviation. N = 19.

H R M SD SL 44.7 21.8-44.7 26.1 5.6 Percentages of SL Depth of body 35.3 35.3-40.6 38.8 1.2 Predorsal distance 49.2 48.3-52.8 51.5 1.1 Prepelvic distance 45.9 45.9-52.0 50.2 1.4 Preanal distance 79.0 79.0-82.3 80.9 0.9 Length of dorsal-fin spine 12.5 12.5-18.6 17.3 1.5 Length of pectoral-fin spine 18.6 18.6-24.9 23.5 1.3 Length of adipose fin spine 9.0 9.0-11.5 10.6 0.6 Caudal peduncle depth 14.5 14.5-17.9 16.9 0.8 Dorsal fin to adipose fin distance 19.0 14.0-19.0 15.4 1.2 Length of dorsal-fin base 19.5 19.5-21.5 20.7 0.5 Head length 32.0 32.0-35.8 34.5 1.1 Length of the longer barbel 17.4 17.5-21.3 20.5 0.8 Percentages of HL Head depth 94.4 90.7-96.6 94.1 1.6 Least interorbital distance 39.9 38.3-41.4 39.6 0.8 Horizontal orbit diameter 20.3 20.3-27.1 25.7 1.8 Snout length 51.7 44.0-51.7 48.6 1.6 Least internareal distance 21.0 15.9-21.0 17.9 1.7

Supraoccipital Nuchal plate plate Fig. 6. Dorsal view of nuchal and supraocciptal plates of Corydoras costai spec. nov., UFRJ 7791. Scale bar = 1 mm. lower lips, and isthmus. Gill membranes united to isthmus. Four branchiostegal rays covered by thick layer of skin; distal two rays united at their tips by Infraorbital II branchiostegal cartilage. Teeth on upper pharyngeal tooth plate 33. Teeth on fifth ceratobranchial 30. Nasal, frontal, sphenotic, pterotic-supracleithrum, Infraorbital I and supraoccipital visible externally, all covered by thin layer of skin and bearing minute scattered odontodes. Frontal fontanel elongate, ellipsoid in shape; posterior tip extending into supraoccipital anteriorly, covered by thin layer of skin. Nasal Fig. 7. Lateral view of infraorbital bones of Corydoras slender, slightly curved laterally, mesial border costai spec. nov., UFR 7791. Scale bar = 1 mm. contacting frontal. Frontal quadrangular; anterior expansion in contact with nasal bone, posterior por tion contacting sphenotic and supraoccipital. Sphen otic, entering sphenotic as temporal canal, which otic trapezoid, contacting supraoccipital dorsally, splits into two branches. One branch giving rise to compound pterotic posteriorly, second infraorbital infraorbital canal, and other branch entering frontal ventrally. Pterotic-supracleithrum approximately through supraorbital canal. Supraorbital canal with rectangular, with posterior expansion contacting two branches: epiphyseal, which opens in frontal first dorsal body plate and first lateral line ossicle. bone, and nasal canal. Nasal canal with single open Ventral margin of pterotic-supracleithrum contact ing at each end. Infraorbital canal running through ing infraorbital 2 and cleithrum. Supraoccipital ap entire second infraorbital, extending to infraorbital 1 proximately quadrangular with pointed posterior and opening into two pores. Preoperculomandibular process, separated from nuchal plate by narrow branch gives rise to preoperculomandibular canal, space bridged by integument (Fig. 6). which runs through entire preopercle with three Two infraorbital bones, externally visible, cov openings, leading to pores 3, 4, and 5, respectively. ered by thin layer of skin bearing minute odontodes Body plates with minute odontodes restricted directly attached to infraorbitals. First infraorbital to posterior margins. Nuchal plate partially covered with anterior expansion (Fig. 7); second infra-orbital by skin anteriorly. Cleithrum and medial process of with small, conspicuous posterior process contacting coracoid exposed. Dorsolateral body plates 22 (12), pterotic-supracleithrum. Opercle exposed, compact 23 (2) and 24 (1); ventrolateral body plates 20 (14)- in shape, with angular free border. Preopercle, ex 21 (15); dorsolateral body plates along dorsal fin base ternally visible, slender and covered by thin layer of 5-7 (7); dorsolateral body plates from adipose fin to skin. Opercle and preopercle with minute odontodes. caudal fin base 7 (15); preadipose platelets 2 (12)- Interopercle triangular, covered by thin layer of skin. 3 (3). Parapophyses of fourth and fifth free vertebra Trunk lateral line with 3(6)-4(9) laterosensory reduced, separate from each other, and not fused into canals; two anteriormost canals reduced to small haemal arch. Parapophyses fused into haemal arch ossicles, remaining canals encased in dorsolateral only from sixth free vertebrae. Precaudal vertebrae body plates. Lateral line canal entering neurocra 7 (1)-8 (2)-9 (2); caudal vertebrae 12 (2)-13 (3); 5 (6) nium through compound pterotic, splitting into pairs of ribs, all similar in size, except smaller last two branches before entering sphenotic: pterotic one. and preoperculomandibular, each with single pore. Dorsal fin rounded, its origin just posterior to Sensory canal continuing through compound pter third dorsolateral body plate. Dorsal spine shorter

ries of large irregular dark brown blotches on dorsal and lateral surfaces of body from anteriormost lateral plates to caudal peduncle. Ventrolateral blotches A more elongate than remaining marks. Five well delimited large dark brown blotches from caudal fin base to posterior margin of opercle, along the B junction of dorsal and ventral plates on the midline of body. Minute dark brown dots scattered over en Fig. 8. Pectoral fin serrations of Corydoras costai spec. tire surface of trunk, more concentrated on anterior nov., UFRJ 7791. A. Restricted to the base of the spine 1 border of each lateral body plate. Ventral surface (less than /3 of the spine); B. composed by weak serra of body yellowish. Ground colour of all dorsal-fin tions along the entire posterior margin of the pectoral fin spine. Scale bar = 1 mm. elements light brown; interradial membranes hya line. Ground colour of anal fin rays light brown. Interradial anal-fin membranes with scattered dark than first 1-4 branched rays. Anterior and posterior brown chromatophores on base of fin; remainder borders of dorsal spine smooth. Dorsal-fin rays of fin membranes hyaline. Adipose-fin spine dark I (15), 7 (1), 8 (13) and 9 (1). Adipose fin rounded, brown. Adipose fin membrane with dark brown its origin separated from base of last dorsal-fin ray blotch. Pectoral fin ground yellowish, with dark by 6 (12)-7 (3) dorsolateral body plates. Anal fin brown spine. Pelvic fin yellowish. Caudal fin yel ovoid, its origin located just posterior to 11th to 12th lowish, with 5-7 dark brown bars on entire fin. ventrolateral body plates, coinciding with vertical Colour in life. through posterior margin of preadipose platelets. Body side intense metallic green. Anal fin rays i (15), 5 (1)-6 (14). Pectoral fin triangu Trunk blotches almost invisible because of intense lar, its origin located just posterior to gill opening. brightness of metallic green ground colour. Ossified portion of pectoral spine shorter than first Distribution. Only known from the type locality: three branched rays. Distal tip of spine without small- floodplain swamps adjacent of the upper Rãs river, segmented unossified portion. Posterior border of tributary of the São Francisco river basin, northeast pectoral spine with serrations variable, restricted ern Brazil (Fig. 9). to proximal third to one-half in two specimens, and with serrations on entire posterior border in Etymology. Named costai in honour to the ichthyologist Wilson Costa, who first collected and identified the two specimens (Fig. 8A-B). Pectoral fin rays I, 8 (6). species as new, in 1999. Pelvic fin rays i, 5 (15). Caudal fin bilobed, upper lobe slightly longer. Principal caudal fin rays 7/7 (6); upper procurrent caudal fin rays 4 (6); lower procur Discussion rent caudal fin rays 4 (5)-5 (1). All fins with minute odontodes scattered over all rays. Corydoras costai is a new species occurring in seasonal Colour in alcohol (Figs 1 and 2). Ground colouration swamps adjacent to the upper Rãs river, tributary of head light brown to yellowish. Small dark brown of the São Francisco river basin, northeastern Brazil. blotches scattered over dorsal and lateral surface of The new species shares a unique colour pattern head and snout forming reticulate pattern. Anterior with C. garbei and C. difluviatilis characterized by nares with series of minute brown chromatophores the presence of series of large irregular dark brown more concentrated at margin. Thin dark brown ring blotches on dorsal and lateral surfaces of body from surrounding orbit. Dorsal maxillary barbel light anteriormost lateral plates to caudal peduncle (Figs brown, with minute scattered dark brown dots on 1, 2, 3 and 4). This unique colour pattern differ them dorsal surface. Ventral maxillary and mental bar from two other congeners from the São Francisco bels unpigmented. Opercle and preopercle regions river basin: C. lymnades Tencatt, Vera-Alcaraz, Britto almost dark brown, with few scattered yellowish & Pavanelli, 2013 and C. multimaculatus Steindach areas. Ventral and lower sides of head yellowish. ner, 1907, which have small scattered dark brown Head sides with some scattered chromatophores, blotches on dorsal and lateral surfaces of body (see mainly on snout tip. Ventral regions without chro Tencatt el al. 2013). matophores. Dark brown blotch on middle of snout, Corydoras costai, as well as C. difluviatilis, differ below narines. from all other corydoradines by having parapophy Ground colour of trunk light brown or yellowish. ses of the fourth free vertebra reduced (Fig. 5), and Large dark brown blotch on dorsal limit of cleithrum separated from each other, not fused into a haemal and posterior region of pterotic-supracleithrum. Se arch, while other corydoradines have parapophyses

-9°

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-24°

-57° -54° -51° -48° -45° -42° -39° -36° -33° Fig. 9. Distribution of Corydoras costai ( , type location), C. difluviatilis ( , type location; , paratypes), C. multima culatus ( , type location) and C. limnades ( , type location; , paratypes). The type location of C. garbei was not located. well developed, and contacting each other fused agnose corydoradine species. According to Britto into a haemal arch. These character states were also & Castro (2002), some members of Corydoras have observed by Britto & Castro (2002). Among members weakly developed serrations on the pectoral fin spine of the Corydoradinae, the first haemal arch, formed or serrations are absent, whereas some members of by fusion of parapophyses, is present on the third the genus show well-developed serrations on the or fourth free vertebra (Britto & Castro 2002), while pectoral fin spine. In all members of Aspidoras Ihe in C. difluviatilis and C. costai the first haemal arch ring, 1907 the pectoral fin spines have well developed is present only on the fifth or sixth, respectively. serrations. In the new species herein described, the These character states related to the parapophyses character related to the serrations of the pectoral fin and haemal arch, as well as the colour pattern, pos spine is polymorphic, possessing two distinguish sibly indicates a closer relationship among these two states: one composed by weak serrations on posterior species. margin of pectoral fin spine, restricted to the base 1 Corydoras costai and C. difluviatilis have some of the spine (less than /3 of the spine) (Fig. 8A); and plesiomorphic character states compared to the second composed by weak serrations along the entire group comprising Brochis Cope, 1871 and Corydoras, posterior margin of the pectoral fin spine (Fig. 8B). previously cited in Britto & Castro (2002) and Britto (2003): lack of contact between the supraoccipital and Acknowledgements nuchal plate (Fig. 6), small degree of ossification of the second hypobranchial and large mesial expan Thanks are due to Bruno Costa, Claudia Bove, Jéssica sion on second infraorbital (Fig. 7). These character Ferreira and to Wilson Costa for first identification of states and implicated relationships are detailed and the species as new in 1999 and to Wilson Costa, José discussed in Britto & Castro (2002) and Britto (2003). Leonardo Mattos and Marcelo Britto for the suggestions The degree of development of the pectoral-fin in the manuscript. This study was supported by CNPq spine serrations is an informative character to di (Conselho Nacional de Desenvolvimento Científico e

Tecnológico – Ministério da Ciência e Tecnologia) and Eschmeyer, W. N. (ed.) 2014. Catalog of fishes: gen FAPERJ (Fundação de Amparo à Pesquisa do Estado do era, species, references. Electronic version. http:// Rio de Janeiro). research.calacademy.org/research/ichthyology/ catalog/fishcatmain.asp [accessed 01 October 2014]. Ferraris, C. J. Jr. 2007. Checklist of catfishes, recent and References fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418: 1-628. Axenrot, T. E. & Kullander, S. O. 2003. Corydoras diphyes Fuller, I. A. M. & Evers, H. G. 2005. Identifying Corydo (Siluriformes: Callichthyidae) and Otocinclus mimu radinae catfish. Aspidoras-Brochis-Corydoras-Scle lus (Siluriformes: Loricariidae), two new species romystax & C-numbers. 384 pp., Worcestershire/ of catfishes from Paraguay, a case of mimetic as Rodgau, UK (Ian Fuller Enterprises/A.C.S. GmbH sociation. Ichthyolocial Exploration of Freshwaters (Aqualog)). 14 (3): 249-272. Reis, R. E. 1997. Revision of the Neotropical genus Hoplo Britto, M. R. 2003. Phylogeny of the subfamily Corydo sternum (Ostariophysi: Siluriformes: Callichthyidae) radinae Hoedeman, 1952 (Siluriformes: Callichthyi with the description of two new genera and three dae), with a definition of its genera. Proceedings of new species. Ichthyological Exploration of Fresh the Academy of Natural Sciences of Philadelphia waters 7: 299-326. 153: 119-154. – – 1998. Anatomy and phylogenetic analysis of the – – & Castro, R. M. 2002. A new corydoradine catfish neotropical callichthyid catfishes (Ostariophysi, (Siluriformes: Callichthyidae) from the upper Para Siluriformes). Zoological Journal of the Linnean ná and São Francisco: the sister-group of Brochis and Society 124: 105-168. most of Corydoras species. Copeia 2002: 1006-1015. – – 2003. Family Callichthyidae (armored catfishes). Pp. – – & Lima, F. C. T. 2003. Corydoras tukano, a new species 291-309 in: Reis, R. E., Kullander, S. O. & Ferraris, of corydoradine catfish from the rio Tiquié, upper C. J. (eds). Check list of the freshwater fishes of rio Negro basin, Brazil (Ostariophysi: Siluriformes: South and Central America. 729 pp., Porto Alegre Callichthyidae). Neotropical Ichthyology 1: 83-92. (EDIPUCRS). – – , Lima, F. C. & Hidalgo, M. 2007. Corydoras ortegai, a Schaefer, S. A. & Aquino, A. 2000. Postotic laterosensory new species of corydoradine catfish from the lower canal and pterotic branch homology in catfishes. río Putumayo in Peru (Ostariophysi: Siluriformes: Journal of Morphology 246: 212-227. Callichthyidae). Neotropical Ichthyology 5 (3): 293- Taylor, W. R. & Van Dyke, G. C. 1985. Revised pro 300. cedures for staining and clearing small fishes and Davis, J. I. & Nixon, K. C. 1992. Populations, genetic other vertebrates for bone and cartilage study. variation, and the delimitation of phylogenetic spe Cybium 9: 107-109. cies. Systematic Biology 41 (4): 421-435. Tencatt, L. F. C., Vera-Alcaraz, H. S., Britto, M. R. & De Queiroz, K. 2007. Species concepts and species de Pavanelli, C. S. 2013. A new Corydoras Lacépède, limitation. Systematic Biology 56: 879-886. 1803 (Siluriformes: Callichthyidae) from the rio São Francisco basin, Brazil. Neotropical Ichthyology 11 (2): 257-264.

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